Picture the scene: you're going out to eat at one of London's hippest new restaurants. You've dressed up and are ready for a night of intimate fine dining – trouble is, first you've got to find the place and unlike Covent Garden, there are no helpful tourist signs in the maze of quiet residential streets in Kilburn, Dalston or Brixton.

This is dining out with a difference – underground, "pop-up" restaurants in private homes are the latest foodie fad to hit London. From creative cuisine in Kilburn at MsMarmiteLover's The Underground Restaurant to nine-course vegetarian Japanese eating on slouchy sofas in Horton Jupiter's beatnik flat, called The Secret Ingredient, in east London, guerrilla dining is at the cutting edge of eating out, provided you can find the location in the first place. Even celebrities and famous restaurants are getting in on the act, with Jo Wood opening her home to paying guests and Mosimann's launching a pop-up restaurant on the bank of the Thames during the Henley Regatta. By their very nature you won't find any neon signs or overt advertising for these gigs – it's all done by word of mouth and the internet.

Although hot in London, these underground eateries are not new. In the US, roving supperclubs such as The Ghetto Gourmet and Red Box Bistro have sizzling reputations and serious waiting lists. In Cuba, paladares are as much part of the culture as cigars and mojitos. It's tempting to think that modern supper clubs are just glorified dinner parties, but the unstoppable American Jim Haynes proves this is a myth. He has been running a weekly restaurant from his apartment in Paris for 30 years and has seen 130,000 people pass though his doors.

So why do people go? Is it the atmosphere or the sense of adventure in eating a surprise set menu in a stranger's home? Is it all about the food, or nosiness? Or is it the illicit nature of these borderline legal set-ups? To find out I decided to start my own – the Savoy Truffle Supperclub.

My husband, Gav, is a professional chef. We love having friends for dinner and they started suggesting we open our house to paying guests. Knowing this was the start of something bigger, we decided to give it a go. It would stretch Gav's cooking skills and our kitchen's capacity, while we'd share the kind of food and atmosphere we'd like to create in our own restaurant one day in the comfort and security of our own home.

There's something both anarchic and liberating about just going for it and when you start off in an underground fashion (no fire doors, drinks licence etc). There is a huge amount of trust involved. But, as one of the pioneers behind the zeitgeist of underground eating in Britain, MsMarmiteLover, explains, this is part of the appeal. "In a restaurant there's a divide between the customer and the kitchen. I like the transparency of a home restaurant; you can visit the kitchen, chat to the chef ... if things are busy and you need water, you can get it yourself. It breaks down the barriers that exist in usual restaurants."

Although we were essentially cooking for friends, we decided "selling" alcohol would put us in dodgy territory, not just legally but morally. Alcohol is how regular restaurants make most of their profits but in the undergrounds, it's the food and the experience that matter, not the bottom line. Most "pop-up" restaurants are free or suggest a nominal donation to cover costs, usually somewhere between £15 and £30. "I always end up breaking even," confirms Jim Haynes of the discretionary contribution he asks of his 70 or so guests each week. This also means your guests are not formally paying, which is another difference between the mainstream and the pop-up.

Once we'd got the over the legal aspects, we moved on to converting our bijou front room into a bona fide dining room. Stuffed with books and clutter, furniture and plants, it was hard to imagine how many tables and chairs we'd be able to squeeze in.

Lots of emails later, we'd rounded up 14 guinea-pigs brave enough to trek to south London and try our prototype pop-up night. Another feature of pop-up restaurants is that they are social events, where guests can interact – you could be sitting next to a stranger, and equally odd and exciting for us was the prospect of strangers coming to our house to eat. What unites everyone is a love of food and a thirst for the new – with the incentive that they get to nose through our photo collection, check out our books and see what we keep in our bathroom cabinet. As MsMarmiteLover explains: "It's a little bit Come Dine With Me, a little bit MasterChef and a little bit Through The Keyhole. It's intimate and sociable. Different tables can talk to each other and there are no sittings. People arrive at 7.30 and stay as long as they like. I don't believe food should be rushed."

In many ways, pop-up restaurants are a return to real eating, when dining out was a social event worth dressing up for and getting excited about, and food was about fresh, seasonal ingredients cooked well but without gimmickry. Our restaurant would be the same, partly because we couldn't fit in tables for two, so diners would have to mix and mingle on larger tables – and if they wanted to switch around, that would be fine, too.

Gav spent weeks thinking about his menu, refining it and testing out canapés and sauces in our tiny kitchen – would people be too full after a poached egg floated atop a bowl of asparagus velouté with a Parmesan crisp? Would it be a tragedy to blitz all those lovely green spears into a soup rather than serve them fresh? Yes on both counts. I spent the build-up to the big night begging tables and chairs from friends and schlepping from shop to shop in search of just the right kind of shot glass for serving sorbet in (a straight, cylindrical double-shot glass). As the evening got closer, the pressure built up and the standards were raised. We'd gone from thinking we'd squeeze people in wherever and serving food on our ramshackle plates to planning with military precision how we could move our sofa and armchair into our bedroom, as well as anything in the kitchen that wasn't needed for the menu. Our car became a dumping ground for toasters and novelty oils. Gav borrowed plates from his restaurant so each table would have matching crockery.

By the time our guests arrived, I still hadn't printed menus. Instead I took a blackboard outside and chalked up what we would be eating while serving our diners a welcome glass of Prosecco in the garden. I worried this was amateurish, but one guest, Amy, said being able to enjoy a relaxed aperitif in a tranquil garden and chatting to the chef and guests was a highlight. "It was lovely to be drinking sparkly in the garden on a sunny evening. At restaurants you are either stood on the road or more often then not you cannot get outside because all the tables are taken."

Despite a frantic 24 hours of building tables, reducing stocks, pureeing peas and broad beans, remaking the treacle tarts – the first batch were "a bit too chewy", according to our sous chef and friend Bob – and running to the shop four times for forgotten ingredients, the evening itself was relatively smooth. Strangers and friends mingled, and people popped by the kitchen to see what was going on and were impressed by the relaxed atmosphere. Although I was waitressing I still got to chat with each table (and enjoy a slurp of red wine) and it was hugely satisfying to be able to tell intrigued guests how much work went into the dishes and that the veg was supplied by a guest from his farm seven miles away – where else could you get provenance like that or so few food miles?

After canapés of pork balls and apple and tarragon aioli, haddock croquettes and parmesan choux puffs, asparagus hollandaise with a poached Cotswold Legbar hen's egg and pancetta to start, rack of lamb, pea and broad bean puree, spring greens and potato dauphinoise, then gin and tonic sorbet and treacle tart, the room was buzzing and waistlines were bulging. "It's surprising how much it feels like a restaurant and not just your lounge," commented my friend Jillian.

We went out to have coffee with our guests feeling proud and elated – and already planning the Savoy Truffle Supperclub's next pop-up night.